In Wetmore U.S. Pat. No. 3,243,211, several types of novel connectors are disclosed. Electrical connectors according to the Wetmore patent, the disclosure of which is incorporated by reference herein, include a dimensionally heat-unstable member such as a sleeve in which is placed a ring or ball-shaped solder insert. In a typical connector of this type, both ends of the member or sleeve are open to receive the electrical conductors that are to be connected. The connector is then heated, causing the member or sleeve to shrink and firmly grip the conductors. The heat also causes the solder to flow and form a soldered connection between the two electrical conductors. The sleeve acts to contain the movement of the solder so that a good soldered joint is assured.
In general, such members or sleeves are made of a material capable of having the property of plastic or elastic memory imparted thereto and are expanded under heat and pressure to a diameter greater than their normal diameter and cooled while under pressure. A sleeve treated in this manner will retain its expanded position until it is again heated to above its heat-recovery temperature at which time it will recover to its original shape. Examples of material useful in forming such dimensionally heat-unstable recoverable members may be found in Currie U.S. Pat. No. 2,027,962 and Cook et al. U.S. Pat. No. 3,086,242, the disclosures of which are incorporated herein by reference. Polymeric materials which have been cross-linked by chemical means or by irradiation, for example, with high-energy electrons or nuclear radiation, such as those disclosed in the Cook et al. patent, are preferred for use in the present invention. Noncrystalline polymeric materials exhibiting the property of plastic or elastic memory, such as polyurethane, inomers, etc, could also be used in practicing the present invention. The connector of the present invention is equally useful with sleeves made from materials having either plastic or elastic memory; consequently, as used herein, the terms "elastic memory" and "plastic memory" are used interchangeably and are intended to be mutually inclusive.
Recoverable members or sleeves of this type are extremely useful in the making of insulated soldered connections between electrical conductors such as between a terminal on a piece of electrical apparatus and a wire, or between two wires. Generally, this is accomplished by providing the recoverable sleeve with an internal ring of solder, pasing the electrical conductors into the two ends of the sleeves until the conductive portions of the conductors are located within the solder ring, and heating the assembly so that the sleeve tries to recover to its original shape and the solder melts and joins the two conductors. The result is a good electrical connection which is insulated and protected by the sleeve.
In Ellis U.S. Pat. No. 3,525,799, which is incorporated herein by reference, there are disclosed fusible inserts, other than solder, for sealing a connector so as to prevent extrusion of the melted solder and also for properly locating a conductor. As disclosed therein, these fusible inserts are generally made from any material that is capable of being rendered flowable by the application of heat. However, preferred materials are thermoplastic materials such as polyolefins, polyamides and polyesters.
It has been found that under certain circumstances the Wetmore and Ellis devices have insufficient mechanical strength to properly maintain alignment of the conductor and, for example, a terminator such as a mass termination connector (MTC) wafer terminator. An MTC wafer terminator is a termination device employed by Raychem Corporation. However, the problem of aligning the conductor and this particular terminator is common to many other types of devices as well. If there is insufficient alignment of the conductor and terminator, it is very likely that a poor electrical connection will result. It would thus be desirable to have a termination device that has sufficient strength to properly align electrical components so as to maintain good electrical contact.
Accordingly, it is an object of the invention to have a termination device with sufficient strength so as to properly align electrical components and maintain good electrical contact.
This and other objects of the invention will become more apparent after reference to the following description, considered in conjunction with the accompanying drawings.